Chromatic dispersion within optical systems causes wavelength-dependent group delay variations that limit data rates, increase bit error rates and otherwise corrupt transmission of optical signals. Measuring chromatic dispersion of an optical system enables performance limitations of the optical system to be predicted. Additionally, once the chromatic dispersion is characterized it can be compensated for to improve system performance.
Typically, chromatic dispersion measurements are performed by characterizing the group delay of optical test signals at various optical wavelengths measured relative to a reference signal. Chromatic dispersion is readily measured when the measurement access points of the optical system are available to a single chromatic dispersion measurement instrument. However, optical systems such as installed fiber networks and other types of communication systems have access points that are physically remote from each other, making chromatic dispersion measurements using a single measurement instrument unfeasible. One approach to chromatic dispersion measurements of such optical systems transmits the reference signal from a local access point to a remote access point of the system using a separate optical fiber. Temperature variations, mechanical stress and other environmental effects on the fiber induce variations in the reference signal that reduce the accuracy and repeatability of the chromatic dispersion measurements. An alternate approach multiplexes the reference signal and the optical test signals within the optical system being characterized. While the multiplexing substantially reduces the impact of environmental effects on the chromatic dispersion measurements, this approach involves additional modulators and detection elements which increase the cost and complexity of the measurements. Accordingly, there is a need for a scheme for measuring chromatic dispersion of optical systems having remote access points, that is independent of environment effects and that has low cost and complexity.